Borage, a hardy annual herb often called the starflower, is widely cultivated for its ornamental blue flowers and its highly valued seed. This seed is a prime source of gamma-linolenic acid (GLA), an omega-6 fatty acid used in dietary supplements. Understanding the seed’s unique appearance is necessary for successful cultivation and commercial oil extraction.
Detailed Physical Characteristics
The borage seed, technically classified as a nutlet, is relatively large compared to many other herb seeds. Each nutlet measures approximately 4 to 5 millimeters in length. This size makes it easy to handle for direct sowing in the garden.
Its shape is angular and oblong, often described as teardrop-shaped or resembling a small peanut. It features a pronounced flat tip on one side, which helps distinguish it from the rounded seeds of other garden plants. Mature seeds range in color from dark brown to a deep, rich black, sometimes appearing mottled.
A defining feature is the seed’s surface texture, which is coarse and rough, not smooth. This pitted or slightly ridged surface is characteristic of nutlets produced by plants in the Boraginaceae family. The combination of dark color, angular shape, and rough texture provides a reliable profile for identification.
Seed Formation and Harvesting
Borage seeds develop after the plant’s signature blue flowers fade and drop. The seeds form within the persistent calyx, a cup-like enclosure that protects the developing nutlets. They are created in clusters of four at the base of the flower.
As the seeds mature, their color shifts from pale green or light brown to their final dark, almost black hue. Once ripe, the plant releases the seeds quickly, causing them to easily detach and fall to the ground. This tendency explains why borage readily self-seeds in a garden environment.
Successful seed harvesting requires frequent checks due to this rapid drop-off tendency. Growers typically collect the nutlets by shaking the dry flower heads over a container once the protective bracts have turned brown and the seeds are dark. This gravity-assisted method capitalizes on the mature seed’s loose attachment.
Practical Identification and Storage
The physical properties of the borage seed aid in proper identification, especially when distinguishing them from common garden weed seeds. The combination of the large, angular shape and the coarse, rough texture serves as a marker against smaller, smoother contaminants. Inspecting the seeds for their consistent dark color and absence of a smooth coating confirms their identity.
Proper storage is necessary to maintain the seed’s viability for planting or its quality for oil pressing. The collected nutlets must be thoroughly dried for at least 24 to 48 hours at room temperature to prevent mold or rot. Storing them in a cool, dark, and dry environment, such as a paper envelope or an airtight container, minimizes the degradation of the fatty acids. Under these conditions, the seeds can remain viable for up to three to five years.